Problems with programmable Honeywell thermostat and heating. New batteries put in a week ago.

Basically it isn't necessarily following the scheduled program. Get up in the morning and the house is cold, cold, cold.

The fuse box has a line run to the furnace. The line runs through a mounted switch (metal box w light type switch) on the furnace body, then into the furnace where it is pigtailed to the furnace and the thermostat I'm guessing. When I go downstairs and flip the switch off and then right back on the furnace kicks in and will heat for some time. Eventually it will stop. Sometimes in an hour, sometimes in 6 hours. Every time I go down and flip the switch off/on the furnace kicks in again.

I have seen the thermostat give the sign that it needs new batteries and I replaced them.

I imagine the next thing to do is try to replace the thermostat and see if that fixes the problem. Does it make sense that the thermostat is the likely culprit? If there was a sensor problem or hardware problem in the furnace why would flipping the switch temp fix this?

I have not had to reset the breaker at all. I suppose I could replace the switch and check to make sure the pigtails are all tight and there isn't a loose connection that separates and then comes back together?

Ideas? I know it's time to try some things and see what sticks.

If anything I've said isn't clear let me know. I can also post pics if needed.

Shut the power off, and go through and check all the connections including the thermostat wires both at the furnace and thermostat. Leave the thermostat hanging by its wires. Turn the power back on and let the furnace run until it quits again. Then short the red and white wires together at the thermostat. If the furnace fires up, the problem is in the thermostat. If not, likely it is the control board. They are expensive, but not too hard to change if you carefully note where all the wires go.

Well, being as that the furnace was already off when it was too cold to not be running I simply checked to connections at the thermostat and shorted the wires as you mentioned and *poof* the furnace lit up.

So I'll make sure everything else looks fine and see if a new thermostat does the job.